Dash-pot



L H. DORAN.

DASH POT.

APPLgcATmN man ocT. 1.1. 1911.

Fig. l.

Patented om. 12,1920.

Illu" I lill lump Ill

/5 I Inventor:

John HDoran, b9 His oflttorjneg.

UNITED STATES PATENT OFFICE.

JOHN H. DURAN, OF SCHENECTADY, NEW YORK, .SSIGNOR TO GENERALyIIEIJLC'LRIC COMPANY, A CRPORATION OF NEW YORK.

DASH-POT.

To LU whom it may concern:

Be it known that 1JoHN H. DORAN, a citizen of the United States,residing at Schenectady, in the county of Schenectady, State of NewYork, have invented certain new and useful Improvements in Dash- Pots,of which the following is a specification.

The present invention relates to dash pots and particularly to dash potsintended for use in reducing axial vibrations of a rotating member whichhas a limited amount of axial play. @ne application of my invention isin connection with elastic fluid turbines for reducing axial vibrationsof the rotor or rotors thereof, and it is articularly intended for usewith radial ow turbines having oppositely rotating wheels in which theaxial thrust is balanced by means of pressure disks upon which elasticfluid acts, the pressure increasing or decreasing on such disks when thewheels move axially to maintain such wheels incorrect position.

.The object of my invention is to provide an improved dash pot whichwill be simple to construct and very effective in operation.

For a consideration of what I believe to be novel and my invention,attention is direct-ed to the accompanying specification and the claimsappended thereto.

In the drawing, Figure 1 is a vertical sectional view of a dash potembodying my invention,and Fig. 2 is a similar view of a modification.

Referring to the drawing, 5 indicates a rotating shaft which may be, forexample, an extended end of a turbine rotor shaft or a separate shaftsuitably coupled toa main rotor shaft. On its end is ka thrust collar 6held in position by nuts 7 and en gaging on opposite side with rings ofballs 8 and 9. The races for the rings of balls 8 and9 are formed byannular grooves in opposite sides of the thrust collar 6 and bycomplementary annular grooves in disks 10 carried in a holder 11. Theholder 11 is xed in a housing 12 formed at the central portion of apiston 13 which slides in a cylinder 14. Between the cylinder and pistonare suitableA packing rings 132L located in grooves in the piston. Oneend of the cylinder is closed by a plate 15 having a bearing sleeve 16through which shaft 5 extends, and the other end is closed by thecylinder head 17. In cylinder head 17 are Specification of LettersPatent.' Patented Oct. 12, 1920 Application filed October 17, 1917.Serial No. 197,159.

one or more valves 18 which are pressed to their seats by springs 19 andopen toward' the piston 13.Y Each spring 19 is located between a frame20, which forms a guide for a valve stem and a nut and washer 21 on theend of such valve stem. Over the cylinder head 17 is fastened' a casing22 having a corrugated or fluted wall 23 which forms a sort of diaphragmwhich may be expanded and contracted by pressure.' ommunicating with thechamber within casing 22 is a passage 24 to which fluid under pressure,for example oil, is supplied through a pipe 25 which may lead from anysuitable source. At 26 is a drain pipe which may lead to a suitabledrain reservoir.

In operation fluid underV pressure is supplied Athrough pipe 25 andpassage 24 and sets up a pressure in the casing 22. This causes the wall23 to distend, giving it a tendency, when the pressure of the fluid onit is slightly decreased, to move toward the cylinder head 17. Fluidalso passes through the valves 1S and fills the space` between the head17 and the end ofthe piston 13 so that the pressure on opposite sides ofthe valves 1S is substantially the same and' the springs 19 hold themlto their seats. Now if the rotor element vibrates axially such vibrationwill betransmitted to the piston 13 causing it to reciprocate back andforth. Such vibrations, however, will be quickly dampened out for ontheslightest movement of the piston rtoward the right fluidV under pressurewill be quickly 2fed through the valves 18 thereby maintaining thepressure of the fluid on the face of the piston 13 and resisting itsreturn movement toward the left. Return movement toward the left canonly be affected by the piston forcing fluid by the piston rings 13aMand as these make a close fit, any quick movement toward the left willbe prevented. Leakage past the piston rings 13a is drained away by 'pipe26. The purpose of the casing 22 'having corrugated wall 23 is to alwaysmaintain a supply of fluid under pressure directly adjacent the valves18 which fluid will be instantly pressed through the valves when thepiston moves to quickly re-establish the pressure on the piston head.The corrugated wall being distended always exerts a pressure toward thecylinder head 17 and maintains the pressure within the chamber formed bycasing 22. Due to this arrangement and the ample valve'area V providedby the valves 18, the apparatus is verysensitive' and quick acting and acon- Yetant fluidiv pressure VWill be continuously maintained on theVpiston head, and also Within casino" 22." Y

The modificationof Ifig. 2 is similar to that of Iiig. 1, except thatfluid pressure is applied to both Vsides of the pistonV instead of toonly one side. VTo this end theV plate is provided vWitlivalv'es' 27similar to valves 18,

` `opening toward the piston and over the plate V15V is fixed-a casing28 forming an annular chamber 29 which is connected to thechamber Withincasing 22 by a conduit 30. In

the conduit 8O is a Vent valve 31 Which mayV be opened to permit theescape of air. A

patent statutes,'-I have described the prin-- ciple of operation of myinvention, together with the apparatus which I now consider torepresentk the best embodiment thereof; but I desire to have itunderstood that the apparatus shown lis only illustrative 'and that theinvention canV be carried out by other means. Y

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

V1. In a dash pot, the combination of a cylinder having `a head, apiston in the cyl- V inder, a valve in the head of the cylinder whichopens toward the piston, a Wall forming a chamber in front of thecylinder head,

means for supplying fluid, to said chamber, and means-for maintainingsaid fluid in the chamber under pressure `whereby when the piston movesVfluid will be quickly forced through said valve.

Y l2. InV a vdash pot, the combination of av cylinder having a head, apiston in the cylinder, a valve inthe head ofthe cylinder which openstoivard'the piston, a Wall forining a `chamber in front of the cylinderhead, means forV supplying fluid under pressure to said chamber, andmeans Which exerts aY pressure onV the fluid tending to force it throughthe valve.

3. In -a'vd'ash pot, the combination of a cylinderrhaving a head, Vapiston in the cylinder, valve means inthe head 'Which opens tovvard thepiston and is biased to closed position, a casingv having a kdistendableWall which fits over'the cylinder head to form a chamber, and means forsupplying fluid under ,pressure to said chamber.

it. In a dash pot, the combination of a cylinder, a piston therein, endWalls for the cylinder, valves in said Walls Which open toward thepiston, Walls forming chambers iIl front of each of said end Walls,means for l supplying fluid, to said chambers, and means for maintainingsaid fluid in the chambers under: pressure .whereby when the pistonVmoves fluid will be quickly forced through said valves., f i

5.- In a. dash pot, the combination of a cylinder, a piston therein, endWalls for the cyl- V inder, valves in said Walls Which open toward thepiston, casings forming chambers in front'ofeach of said` end Walls,means for supplying fluid under pressure to said chambers, and meanswhich exerts a pressure lon the fluid tending to force it through thevalves. v

6. In a dash pot, the combination of a cylinder, a piston therein, endWalls for the cylinder,` valves in said Walls which open toward thepiston, casings forming chambers in frontof each of saidA endvvalls, aWallof at least one of said chambers being adapted to be distended, andmeans for supplying fluid under pressure to said-chambers.

7. In a dash pot, the combination of a cylinder, a piston therein, end.Walls for the cylinder, valves in said Walls which open to-vy Ward thepiston, casings forming chambers infront of each of said end Walls, aWall of one of said casings being adapted to be distended, a conduitconnecting said chambers` together, and a conduit for supplying fluid'under pressure to one of said chambers.

8. The combination With a rotating shaft susceptible Vof axialvibrations, of means for Y dampening such vibrations comprising Vapistonconnected to the shaft, a cylindery in whichV the piston may move,'a head for the cylinder, valve means in the head, a casing forming AaVchamber in front of the head, and meansfor supplying fluid underpressure to said chamber, said casing comprising means Whichy exerts apressure tending toV Vforce Huid through the valves. Y

In Witness whereof, I have hereunto set my hand this 16th dayV ofOctober, 1917.

' Joiiiv ii. noimiv.

